Wireless communication device

ABSTRACT

The present technology relates to a wireless communication device that is adapted to be capable of effectively utilizing frequency resources. The wireless communication device is a wireless communication device that is connected to one or a plurality of target wireless communication devices, and that includes: a transmission unit that transmits, to another wireless communication device, a measurement request signal requesting measurement related to a propagation status of a signal from the target wireless communication device; and a receiving unit that receives a measurement request response signal transmitted from the another wireless communication device in response to the measurement request signal, the measurement request response signal including a result of the measurement. The present technology can be applied to a wireless base station and a wireless terminal station.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Phase of International PatentApplication No. PCT/JP2018/046019 filed on Dec. 14, 2018, which claimspriority benefit of Japanese Patent Application No. JP 2017-253151 filedin the Japan Patent Office on Dec. 28, 2017. Each of theabove-referenced applications is hereby incorporated herein by referencein its entirety.

TECHNICAL FIELD

The present technology relates to a wireless communication device, andin particular, relates to a wireless communication device that isadapted to be capable of effectively utilizing frequency resources.

BACKGROUND ART

Conventionally, various technologies are proposed as technologiesrelated to wireless communications.

For example, as a technology related to wireless communications, thereis proposed a technology in which a frame is given/received betweenwireless communication devices such as a wireless base station (AccessPoint (AP)) and a wireless terminal station (Station (STA)) so as tosupport cooperative and sectorized transmission (refer to, for example,Patent Document 1).

CITATION LIST Patent Document

-   Patent Document 1: Japanese Patent Application Laid-Open No.    2016-526856

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

Incidentally, in recent years, with the spread of wireless communicationsystems in conformity with the Institute of Electrical and ElectronicEngineers (IEEE) 802.11 that are wireless communication standards, thereis a case where a plurality of wireless base stations (access points(APs)) is installed at home.

According to the current standards, a wireless base station (AP) to beconnected is determined by independent judgment of a wireless terminalstation (station (STA)). Therefore, there occurs a phenomenon calledSticky Client in which even if, for example, movement of a wirelessterminal station (STA) causes a wireless base station (AP) serving asthe optimum connection destination to change, the wireless terminalstation (STA) tries to keep connection to the wireless base station (AP)that is in a connection state.

As the result, efficiency in the use of frequency resources decreases,which disables efficient communication in each Basic Service Set (BSS).

The present technology has been devised in consideration of such asituation, and is adapted to be capable of effectively utilizingfrequency resources.

Solutions to Problems

A wireless communication device according to a first aspect of thepresent technology is a wireless communication device that is connectedto one or a plurality of target wireless communication devices, and thatincludes: a transmission unit that transmits, to another wirelesscommunication device, a measurement request signal requestingmeasurement related to a propagation status of a signal from the targetwireless communication device; and a receiving unit that receives ameasurement request response signal transmitted from the anotherwireless communication device in response to the measurement requestsignal, the measurement request response signal including a result ofthe measurement.

According to the first aspect of the present technology, in a wirelesscommunication device connected to one or a plurality of target wirelesscommunication devices, a measurement request signal requestingmeasurement related to a propagation status of a signal from the targetwireless communication device is transmitted to another wirelesscommunication device, and a measurement request response signaltransmitted from the another wireless communication device in responseto the measurement request signal is received, the measurement requestresponse signal including a result of the measurement.

A wireless communication device according to a second aspect of thepresent technology includes: a receiving unit that, with respect to oneor a plurality of target wireless communication devices connected toanother wireless communication device, receives a measurement requestsignal requesting measurement related to a propagation status of asignal from the target wireless communication device, the measurementrequest signal having been transmitted from the another wirelesscommunication device; a signal generation unit that, in response to themeasurement request signal, generates a measurement request responsesignal including a result of the measurement related to the propagationstatus of the signal from the target wireless communication device; anda transmission unit that transmits the measurement request responsesignal to the another wireless communication device.

According to the second aspect of the present technology, there isprovided a wireless communication device in which: with respect to oneor a plurality of target wireless communication devices connected toanother wireless communication device, a measurement request signalrequesting measurement related to a propagation status of a signal fromthe target wireless communication device is received, the measurementrequest signal having been transmitted from the another wirelesscommunication device; in response to the measurement request signal, ameasurement request response signal including a result of themeasurement related to the propagation status of the signal from thetarget wireless communication device is generated; and the measurementrequest response signal is transmitted to the another wirelesscommunication device.

A wireless communication device according to a third aspect of thepresent technology includes: a receiving unit that receives a connectionrequest inducing signal that has been transmitted from a first wirelesscommunication device connected, and that gives an instruction ontransmission of a connection request signal requesting connection to asecond wireless communication device determined as its own newconnection destination; and a transmission unit that transmits theconnection request signal to the second wireless communication deviceaccording to the connection request inducing signal.

According to the third aspect of the present technology, there isprovided a wireless communication device in which: a connection requestinducing signal that has been transmitted from a first wirelesscommunication device connected, and that gives an instruction ontransmission of a connection request signal requesting connection to asecond wireless communication device determined as its own newconnection destination is received; and the connection request signal istransmitted to the second wireless communication device according to theconnection request inducing signal.

Effects of the Invention

According to the first to third aspects of the present technology,frequency resources can be effectively utilized.

It should be noted that the effects described herein are not necessarilylimited, and may be any one of the effects described in the presentdisclosure.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating an example of topology of a wirelessnetwork.

FIG. 2 is a diagram illustrating optimization of connectiondestinations, and a packet sequence.

FIG. 3 is a diagram illustrating a configuration example of a triggerframe.

FIG. 4 is a diagram illustrating an example of a Common Info field.

FIG. 5 is a diagram illustrating an example of a User Info field.

FIG. 6 is a diagram illustrating optimization of connectiondestinations.

FIG. 7 is a diagram illustrating an example of a measurement requestframe.

FIG. 8 is a diagram illustrating an example of a measurement responseframe.

FIG. 9 is a diagram illustrating a configuration example of a wirelesscommunication device.

FIG. 10 is a flowchart illustrating connection-destination determinationprocessing.

FIG. 11 is a flowchart illustrating connection-destination changingprocessing.

FIG. 12 is a flowchart illustrating response processing.

FIG. 13 is a diagram illustrating a configuration example of a computer.

MODE FOR CARRYING OUT THE INVENTION

Embodiments to which the present technology is applied will be describedbelow with reference to the accompanying drawings.

First Embodiment About the Present Technology

In the present technology, a wireless base station (AP) designates anappropriate wireless base station (AP), which serves as a connectiondestination of a wireless terminal station (STA), by using a triggerframe (Trigger Frame) defined by, for example, IEEE 802.11ax, andconsequently frequency resources can be effectively utilized.

Hereinafter, in particular, the wireless base station (AP) is referredto as “access point”, and the wireless terminal station (STA) isreferred to as “station”.

As described above, in a case where a station independently selects anaccess point that serves as a connection destination, there occurs aphenomenon called Sticky Client in which even when movement or the likeof the station causes the optimum connection destination to change, aconnection at the present point of time will be maintained.

Specifically, as shown in, for example, FIG. 1, it is assumed that thereare two access points AP A and AP B, the wirelessly communicatablecommunication ranges of which partially overlap each other.

In addition, it is assumed that stations STA1 and STA2, which arelocated in proximity to the access point AP A, are in a state of beingconnected to the access point AP A. In other words, it is assumed thatthe stations STA1 and STA2 are in a state of being under the control ofthe access point AP A.

Here, the state in which a station is connected to an access point is astate in which the station transmits a connection request signal(Association Request) to the access point, the access point thentransmits a connection request response signal (Association Response)indicating that a connection is permitted in response to the connectionrequest signal, and consequently the station is associated.

In the state in which the station is associated (connected), the stationand the access point recognize that those devices are mutuallyconnected, and are in a state in which the station and the access pointare capable of communicating with each other.

In addition, in FIG. 1, the stations STA1 and STA2 exist at respectivepositions equidistant from the access point AP A that is a connectiondestination. In other words, a distance from the station STA1 to theaccess point AP A is equivalent to a distance from the station STA2 tothe access point AP A.

Moreover, in this example, although the station STA2 is under thecontrol of the access point AP A, the station STA2 exists at a positionthat is closer in distance to the connectable access point AP B than theaccess point AP A.

Therefore, there is a case where using not the access point AP A but theaccess point AP B as a connection destination of the station STA2enables more efficient communication.

Specifically, for example, it is assumed that the access point AP A andthe access point AP B are both connected to a backhaul, and even if astation is connected to any of the access point AP A and the accesspoint AP B, the station is capable of performing desired communication.In other words, the stations STA1 and STA2, which are under the controlof the access point AP A, both exist at positions connectable to theaccess point AP B.

In addition, it is assumed that the access point AP A, the access pointAP B, the station STA1, and the station STA2 exist within a communicablerange within which communications can be performed thereamong, and thosedevices perform communications using the same frequency resources.

In such a case, when positional relationship among the access point APA, the access point AP B, the station STA1, and the station STA2 is in astate shown in FIG. 1, optimizing connection destinations as shown in,for example, FIG. 2 enables efficiency in the use of frequency resourcesto be enhanced.

It should be noted that in FIG. 2, identical reference numerals are usedto denote parts corresponding to those shown in FIG. 1, and thedescription thereof will be omitted as appropriate. In addition, in FIG.2, the horizontal axis indicates the time. Further, although FIG. 2illustrates a case where the number of stations targeted for theoptimization of connection destinations is two, the number of stationstargeted for the optimization of connection destinations may be one ortwo or more. Moreover, the number of access points that are candidatesof new connection destinations of stations may be two or more.

The upper side of FIG. 2 illustrates an example of a packet sequenceused in a case where connection destinations are not optimized.

In this example, the station STA1 and the station STA2 are under thecontrol of the access point AP A. First of all, the station STA1transmits a signal SG11 that includes one or a plurality of packets tothe access point AP A.

After the signal SG11 is transmitted, the station STA2 transmits asignal SG12 that includes one or a plurality of packets to the accesspoint AP A. However, since the station STA1 cannot transmit a signalduring that time, the station STA1 is in a standby state.

In addition, after the transmission of the signal SG12 ends, the stationSTA1 transmits a signal SG13 to the access point AP A, and after thetransmission of the signal SG13, the station STA2 transmits a signalSG14 to the access point AP A.

Here, the station STA1 and the station STA2 are located at respectivepositions equidistant from the access point AP A that is the connectiondestination, and therefore the signals SG11 to SG14 are transmitted atthe same transmission rate.

In this manner, the station STA1 and the station STA2 performcommunications by being connected to the access point AP A. However, asshown in FIG. 1, the station STA2 exists at a position that is closer tothe access point AP B than the access point AP A.

Accordingly, performing optimization of connection destinations, inother words, handover of a connection destination, and changing theconnection destination of the station STA2 from the access point AP A tothe access point AP B that is closer to the station STA2, enablesefficiency in the use of frequency resources to be enhanced.

The lower side of FIG. 2 illustrates an example of a packet sequenceused in a case where the optimization of connection destinations causesthe station STA2 to be reconnected to the access point AP B, in otherwords, in a case where handover to the access point AP B is performedfor the station STA2.

In this example, the station STA1 is in a state of being connected tothe access point AP A, and the station STA2 is in a state of beingconnected to the access point AP B.

In this case, first of all, the station STA1 transmits the signal SG11to the access point AP A. During that time, the station STA2 waitswithout transmitting a signal in order to prevent the signal from beinginterfered with a signal transmitted by the station STA2 itself.

Subsequently, after the transmission of the signal SG11 ends, thestation STA2 then transmits a signal SG12′ to the access point AP B, andwhile the signal SG12′ is transmitted, the station STA1 waits withouttransmitting a signal.

After the transmission of the signal SG12′ ends, the station STA1transmits the signal SG13 to the access point AP A, and after thetransmission of the signal SG13, the station STA2 transmits a signalSG14′ to the access point AP B.

Here, a distance from the station STA2 to the access point AP B isshorter than a distance from the station STA2 to the access point AP A,and therefore the signal SG12′ and the signal SG14′ are transmitted at atransmission rate higher than that of the signal SG12 and the signalSG14.

In a case where a distance between a station and an access point thatperform communications is short, a propagation loss of a signaldecreases. Therefore, since a signal can be received at strongerreceived power on the receiving side, there is a higher possibility thatthe signal can be correctly received. In addition, there is thus a lowerpossibility that the signal will be retransmitted. In other words, asuccess rate of communication increases. For this reason, by increasingthe transmission rate of the signal with the decrease in distancebetween the station and the access point, higher speed communicationscan be performed.

On the upper and lower sides of FIG. 2, the same transmission request ismade, and results in the same packet sequence. However, since the signalSG12′ and the signal SG14′ are transmitted at a transmission rate higherthan that of the signal SG12 and the signal SG14, the time taken totransmit those signals is shortened.

As the result, in the example in which the optimization of connectiondestinations has been performed shown in the lower side of FIG. 2, thecommunication time is shortened by the time shown in an arrow Q11 incomparison with the example in which the optimization of connectiondestinations has not been performed, and accordingly the next signaltransmission can be performed by using the shortened time period.

For this reason, it is revealed that by performing the optimization ofconnection destinations, communication can be completed in a shortertime period, and frequency resources can be more effectively utilized.

Next, the optimization of connection destinations as shown in, forexample, FIG. 2, in other words, handover of a station to a newconnection destination, will be described.

IEEE 802.11ax that corresponds to next-generation wireless LAN standardsnewly defines a control signal that is called trigger frame (TriggerFrame) having a configuration shown in, for example, FIG. 3.

The trigger frame shown in FIG. 3 can be transmitted to a plurality ofwireless communication devices as destinations, and a Common Info fieldindicated by characters “Common Info” stores common information sharedamong one or a plurality of destinations of this trigger frame.

In addition, the trigger frame is provided with one or a plurality ofUser Info fields indicated by characters “User Info”, and the User Infofield stores individual information provided for each destination ofthis trigger frame.

Besides the above, the trigger frame has a field indicated by characters“FCS”, and a frame check sequence is stored in the field.

The Common Info field of the trigger frame shown in, for example, FIG. 3has a configuration shown in FIG. 4.

The Common Info field shown in FIG. 4 is provided with a trigger typefield (Trigger Type Field) indicated by characters “Trigger Type”.

This trigger type field stores type information indicating a type of asignal that should be transmitted by a wireless communication devicedesignated by a trigger frame in response to receiving of the triggerframe, in other words, a type of a data frame that should betransmitted.

In addition, the Common Info field is provided with a field indicated bycharacters “Length”, and this field stores information indicating alength of a trigger frame (signal length), in more detail, a length of apacket that stores the trigger frame.

Moreover, the Common Info field is provided with a field indicated bycharacters “AP TX Power”, and this field stores trigger frametransmission power information indicating transmission power that iselectric power at the time of transmission of a trigger frame.

In addition, the User Info field of the trigger frame shown in FIG. 3has a configuration shown in FIG. 5.

The User Info field shown in FIG. 5 is provided with: a field indicatedby characters “AID12”; a field indicated by characters “RU Allocation”;a field indicated by characters “Target RSSI”; and the like.

For example, the field indicated by characters “AID12” storesinformation indicating a wireless communication device that shouldtransmit a signal, the type of which is indicated by type information,in response to receiving of a trigger frame, in other words, senderinformation indicating a wireless communication device that is a senderof the signal, the type of which is indicated by the type information.In a case where a trigger frame is provided with a plurality of UserInfo fields, each of those User Info fields stores different senderinformation.

In addition, the field indicated by characters “RU Allocation” storesresource information indicating a frequency resource and a spaceresource that should be used when the signal, the type of which isindicated by the type information, is transmitted in response toreceiving of a trigger frame.

It should be noted that in a case where it is not particularly necessaryto distinguish the frequency resource from the space resource,hereinafter the frequency resource and the space resource are alsomerely referred to as resources.

The field indicated by characters “Target RSSI” stores received powerinformation indicating received power of a signal that should be ensuredas a minimum on the receiving side of the signal when a signal, the typeof which is indicated by type information, has been transmitted inresponse to receiving of a trigger frame. Here, the receiving side ofthe signal, the type of which is indicated by the type information, isbasically an access point that is a sender of the trigger frame.

The trigger frame that is provided with the Common Info field and theUser Info field such as those described above is, for example,transmitted from the access point to the station.

Therefore, when a station indicated by sender information in the fieldindicated by characters “AID12” receives a trigger frame, after thelapse of a fixed period of time from the reception time at which thetrigger frame has been received, the station transmits a signalindicated by type information as a response signal responding to thetrigger frame.

At this point, the response signal is transmitted by using the frequencyresource and the space resource designated by resource informationstored in the trigger frame. In other words, the response signal istransmitted by use of a frequency channel (frequency band) indicated byresource information, and by an antenna defined by the resourceinformation. A difference in space resource of a response signal meansthat a transmission path (path) after the response signal has beentransmitted until the response signal is received differs. Trainingfields of response signals transmitted in space resources that differfrom each other store signals (training) of patterns that differ fromeach other.

Transmission of various kinds of signals is mainly controlled by astation in the past. However, introducing such a trigger frame enablesan access point to manage transmission of a signal by a station.

In the present technology, an access point is adapted to designate anappropriate connection destination of a station by using a trigger framedefined by IEEE 802.11ax.

An example of a series of sequences performed when an access pointdesignates a connection destination of a station will be described belowwith reference to FIGS. 6 to 8.

Incidentally, here, it is assumed that in the arrangement shown in FIG.1, the access point AP A, the access point AP B, the station STA1, andthe station STA2 exist, and the station STA1 and the station STA2 areunder the control of the access point AP A.

First of all, as shown with an arrow Q41 of FIG. 6, the access point APA transmits a measurement request frame (Measurement Request) to theaccess point AP B.

In addition, when the predetermined time elapses after the transmissionof the measurement request frame, as shown with an arrow Q42, the accesspoint AP A transmits a trigger frame (Trigger Frame) to the station STA1and the station STA2 that are under the control of the access point AP Aitself.

Here, the measurement request frame is a measurement request signal thatrequests measurement of distance indicator information that becomes anindicator of a distance from the access point AP B to each station underthe control of the access point AP A. In other words, the measurementrequest frame is a measurement request signal that requests measurementrelated to a propagation status of a signal between the access point APB and a station.

The distance indicator information is, for example, reception intensityof a trigger response frame (Triggered Response) that is a responsesignal responding to the trigger frame, in other words, received poweror the like, at the access point AP B.

It should be noted that the access point AP A may notify the accesspoint AP B of frequency resources and space resources at the time of thetransmission of the trigger response frame, which are assigned to thestation STA1 and the station STA2 respectively.

In addition, the trigger frame transmitted by the access point AP A is atransmission request signal that gives an instruction on transmission ofa trigger response frame for measurement of distance indicatorinformation. A trigger frame having a configuration shown in, forexample, FIG. 3 is transmitted from the access point AP A.

In this case, in the example shown in FIG. 6, the type information isinformation indicating a trigger response frame, and a trigger frame isprovided with two User Info fields. Further, sender information in oneUser Info field is information indicating the station STA1, and senderinformation in the other User Info field is information indicating thestation STA2.

Moreover, the two User Info fields are adapted to store respectivepieces of resource information different from each other. In otherwords, when a trigger response frame is transmitted by the station STA1,for at least either of a frequency resource and a space resource, aresource different from that used when a trigger response frame istransmitted by the station STA2 is used.

For example, in a case where space resources used to transmit twotrigger response frames differ from each other, signal patterns oftraining fields in those trigger response frames differ. Therefore, theaccess point AP B is capable of distinguishing those received triggerresponse frames from each other.

By the transmission of the trigger frames such as those described above,the station is notified (informed) of the transmission timing of thetrigger response frame that is a response signal responding to thetrigger frame, and consequently transmission of a trigger frame/responseframe is induced.

Here, FIG. 7 illustrates an example of a measurement request frame.

In the example shown in FIG. 7, the measurement request frame includes:trigger delay amount information indicated by characters “TriggerDelay”; a trigger body indicated by characters “Trigger Body”; and aframe check sequence indicated by characters “FCS”.

For example, the trigger delay amount information is information thatindicates the elapsed time (delay time) after a measurement requestframe is transmitted until a trigger frame is transmitted.

Here, when a trigger frame has been received, a trigger response frameis transmitted after the lapse of the predetermined time. Therefore, itcan be said that the trigger delay amount information is informationused to identify the transmission timing of the trigger response frame.

In addition, the trigger body is information that includes informationused to identify a station that transmits a trigger response frame, theinformation including, for example, information indicating a frequencyresource and a space resource which are used at least at the time oftransmission of a trigger response frame by a station.

Here, it is assumed that a trigger frame itself is treated as a triggerbody. In other words, for each of the station STA1 and the station STA2,the trigger body includes sender information indicating a station, andresource information indicating a resource used by the station.Therefore, for example, sender information and resource information,which are included in the trigger body, are used as information used toidentify a station that transmits a trigger response frame.

Returning to the explanation of FIG. 6, when a trigger frame istransmitted in the timing shown with the arrow Q42, the station STA1 andthe station STA2 receive the trigger frame.

Subsequently, the station STA1 and the station STA2 refer to senderinformation included in the received trigger frame, and when it isidentified that the station STA1/station STA2 itself is a sender of asignal, the type of which is indicated by type information, in otherwords, here, a sender of the trigger response frame, the station STA1and the station STA2 each transmit a trigger response frame as shownwith an arrow Q43.

These trigger response frames are response signals, each of which istransmitted as a response to the trigger frame that is a transmissionrequest signal.

The station STA1 and the station STA2 each transmit a trigger responseframe on the basis of the User Info field that includes senderinformation indicating the station STA1/the station STA2 itself, andinformation stored (included) in the Common Info field.

For example, the station STA1 and the station STA2 each transmit thetrigger response frame by using transmission power determined by triggerframe transmission power information and received power informationwhich are included in the trigger frame.

In addition, the trigger response frame is transmitted in the timingafter the lapse of the predetermined time from the reception time of thetrigger frame.

The trigger response frame that has been transmitted in this manner isreceived not only by the access point AP A but also by the access pointAP B.

When the access point AP B receives the trigger response frametransmitted from the station STA1 or the station STA2, as shown with anarrow Q44, the access point AP B performs measurement processing(Measurement) for obtaining distance indicator information according tothe measurement request frame received from the access point AP A.

In other words, the access point AP B performs measurement processingrelated to a propagation status of a signal between the access point APB itself, and the station STA1 and the station STA2 on the basis of thereceiving timing of the trigger response frame or the received triggerresponse frame.

For example, in the measurement processing, reception intensity(received power) of the received trigger response frame is measured, andthe reception intensity obtained as a result thereof is used as distanceindicator information as it is.

The shorter a distance from a station, which is a sender of a triggerresponse frame, to the access point AP B, the higher (stronger) thereception intensity of the trigger response frame becomes. Therefore, itcan be said that the reception intensity obtained in this manner isinformation used as an indicator indicating a distance between thestation and the access point AP B.

For example, it is assumed that in a case where positional relationshipamong the access points and the stations is equivalent to that shown inFIG. 1, transmission power for transmitting the trigger response framefrom the station STA1 is the same as transmission power for transmittingthe trigger response frame from the station STA2.

As described above, transmission power for transmitting the triggerresponse frame is determined by the trigger frame transmission powerinformation and the received power information in the trigger frame. Inother words, the transmission power for transmitting the triggerresponse frame, in more detail, received power on the receiving side ofthe trigger response frame, is designated by the trigger frame.

In this case, at the access point AP B, the reception intensity of thetrigger response frame received from the station STA2, which is locatedat a position nearer from the access point AP B itself, must be higherthan the reception intensity of the trigger response frame received fromthe station STA1 located at a position farther from the access point APB itself.

It should be noted that on the basis of the trigger delay amountinformation included in the measurement request frame received from theaccess point AP A, the access point AP B is capable of grasping theapproximate timing in which the trigger response frame is transmitted tothe access point AP B itself.

The reason for the above is that since the time from the receipt of thetrigger frame to the transmission of the trigger response frame ispredetermined known information, on the assumption that the sum of thattime and the time indicated by the trigger delay amount information isthe scheduled time, the time after the lapse of the scheduled time fromthe reception time of the measurement request frame becomes theapproximate arrival time of the trigger response frame.

In addition, here, the example in which the reception intensity is usedas the distance indicator information has been described. However, anykind of information may be used as the distance indicator information solong as the information serves as an indicator of the distance betweenthe access point AP B and the station that is the sender of the triggerresponse frame.

Specifically, for example, the reception time of the trigger responseframe at the access point AP B, the time (delay amount) from thereception time (transmission time) of the measurement request frame tothe reception time of the trigger response frame, the time (delayamount) from the transmission time of the trigger response frame to thereception time, an error property at the time of receiving the triggerresponse frame, a combination of those pieces of information, or thelike, at the access point AP B, may be used as the distance indicatorinformation.

For example, the shorter a distance from a station, which is a sender ofa trigger response frame, to the access point AP B, the earlier thereception time of the trigger response frame becomes, and therefore thisreception time can also be used as an indicator of the distance.

In this case, for example, with respect to the same trigger responseframe, if a difference between the reception time of the triggerresponse frame at the access point AP B and the reception time of thetrigger response frame at the access point AP A is determined, thereception time being indicated by the distance indicator information,the positional relationship among the devices can be grasped. In otherwords, by using the determined difference, it is possible to identify towhich of the access point AP A and the access point AP B the stationthat is the sender of the trigger response frame is located at aposition nearer.

This similarly applies to a case where the time (delay amount) from thereception time of the measurement request frame to the reception time ofthe trigger response frame, or the time (delay amount) from thetransmission time of the trigger response frame to the reception time,is used as the distance indicator information. It should be noted thatat the access point AP B, the approximate transmission time of thetrigger response frame can be identified on the basis of the triggerdelay amount information.

In addition, for example, in general, the longer a distance from astation, which is a sender of a trigger response frame, to the accesspoint AP B, the number of receiving errors occurring at the time ofreceiving the trigger response frame increases, and therefore areceiving error rate (rate of occurrence of receiving errors) increases.Therefore, an error property at the time of receiving the triggerresponse frame, in other words, the receiving error rate, can also beused as an indicator of the distance.

In this case, for example, by configuring the trigger response frame toinclude one or a plurality of frame check sequences, the receiving errorrate at the time of receiving the trigger response frame can be obtainedby computation that uses those frame check sequences. This is becausethe computation that uses the frame check sequences enables whether ornot a signal of a part that includes the frame check sequences couldhave been correctly received, in other words, whether or not a receivingerror has occurred, to be identified.

If the receiving error rate obtained in this manner is used as thedistance indicator information, by comparing the receiving error rate asthe distance indicator information with a receiving error rate at theaccess point AP A, the positional relationship among the devices can begrasped. In other words, it is possible to identify to which of theaccess point AP A and the access point AP B the station that is thesender of the trigger response frame is located at a position nearer.

When the distance indicator information is obtained by the measurementprocessing, as shown with an arrow Q45, the access point AP B transmits,to the access point AP A, the measurement response frame (MeasurementResponse) that includes the distance indicator information obtained as aresult of the measurement processing.

This measurement response frame is a measurement request response signalserving as a response to the measurement request frame that is ameasurement request signal.

For each station that has transmitted a trigger response frame, forexample, the measurement response frame includes a result of measurementcorresponding to the measurement request frame, in other words, distanceindicator information obtained by the measurement processing.

As an example, the measurement response frame can have a configurationshown in, for example, FIG. 8. In the example shown in FIG. 8, themeasurement response frame is provided with a set of a field indicatedby characters “Triggered STA ID” and a field indicated by characters“Measurement Report”, the number of sets being the number of stationsthat have transmitted the trigger response frame.

The field indicated by characters “Triggered STA ID” storesidentification information indicating a station that has transmitted thetrigger response frame. In addition, the field indicated by characters“Measurement Report” stores distance indicator information obtained bythe measurement processing related to the trigger response frametransmitted from the station.

Therefore, in the example shown in FIG. 6, for each of the station STA1and the station STA2, a set of the identification information and thedistance indicator information is stored in the measurement responseframe.

Here, any kind of information that can identify a station may be used asthe identification information. However, for example, sender informationincluded in the measurement request frame can be used as theidentification information as it is.

As described above, the trigger body of the measurement request frameshown in FIG. 7 includes contents of the trigger frame transmitted tothe station just as they are.

In other words, for each of the station STA1 and the station STA2, thetrigger body includes sender information indicating a station, andresource information indicating a resource used by the station.

Therefore, from a frequency resource and a space resource of a receivedtrigger response frame, the access point AP B is capable of identifyingsender information indicating a station that has transmitted the triggerresponse frame.

Accordingly, the access point AP B treats the sender information thathas been identified from the received trigger response frame as theidentification information of the trigger response frame just as it is,and then stores the sender information in the measurement response frameby being associated with the identification information and distanceindicator information.

The access point AP A that receives the measurement response frame alsoknows correspondence relationship between a station under the control ofthe access point AP A itself and sender information (identificationinformation), and therefore the access point AP A is capable of graspingwhich station has the distance indicator information that is associatedwith the identification information.

Incidentally, at the access point AP A, resources, in other words, afrequency resource and a space resource, which are used by a stationunder the control of the access point AP A itself to transmit a triggerresponse frame, are known. Accordingly, resource information indicatingresources of a trigger response frame may be used as identificationinformation.

In this case as well, the access point AP A that receives themeasurement response frame is capable of grasping which station has thedistance indicator information that is associated with the resourceinformation as the identification information.

Returning to the explanation of FIG. 6, when the access point AP Areceives the measurement response frame that has been transmitted fromthe access point AP B, as shown with an arrow Q46, the access point AP Amakes a decision (Handover Decision) as to whether or not to performhandover of a station under the control of the access point AP A itself.

At the time of the decision as to whether or not to perform handover,the access point AP A determines a connection destination of eachstation on the basis of information related to a relative distance tothe station under the control viewing from the access point AP A itself,and the received distance indicator information.

Here, distance indicator information can be used as the informationrelated to the relative distance to the station.

For example, the trigger response frame that has been transmitted in thetiming shown with the arrow Q43 is received by the access point AP A.

Accordingly, the access point AP A also performs measurement processingsimilar to that performed at the access point AP B, and consequentlydistance indicator information can be generated. It is considered thatthis distance indicator information is similar to information obtainedat the access point AP B, the information including, for example,reception intensity, the reception time of the trigger response frame,an error property at the time of receiving the trigger response frame,and the like.

It should be noted that hereinafter, the distance indicator informationobtained by the measurement processing at the access point AP A is alsoparticularly referred to as “distance indicator information DI A”, andthe distance indicator information obtained by the measurementprocessing at the access point AP B is also particularly referred to as“distance indicator information DI B”.

At the time of the decision as to whether or not to perform handover,for example, the access point AP A determines the optimum connectiondestination of each station by comparing the distance indicatorinformation DI A with the distance indicator information DI B for eachstation under the control of the access point AP A itself. In otherwords, optimization of connection destinations is performed.

As an example, a case where distance indicator information is receptionintensity will be described.

In this case, the access point AP A makes a comparison between thedistance indicator information DI A and the distance indicatorinformation DI B, which have been obtained for the station STA1. As theresult, it is revealed that the distance indicator information DI A islonger than the distance indicator information DI B. In other words, itis revealed that the station STA1 is located at a position that isnearer to the access point AP A than the access point AP B.

Meanwhile, the access point AP A makes a comparison between the distanceindicator information DI A and the distance indicator information DI B,which have been obtained for the station STA2, and as the result, it isrevealed that the distance indicator information DI A is shorter thanthe distance indicator information DI B. In other words, it is revealedthat the station STA2 is located at a position that is nearer to theaccess point AP B than the access point AP A.

Accordingly, the access point AP A keeps the access point AP A unchangedas the connection destination of the station STA1 located at a positionthat is nearer to the access point AP A itself, and changes theconnection destination of the station STA2 located at a position that isnearer to the access point AP B than the access point AP A itself to theaccess point AP B.

In other words, in this example, the access point AP A determines, fromthe current connection relationship, that with respect to the stationSTA2, making a reconnection to the adjacent access point AP B enablesmore effective utilization of frequency resources, and consequently theaccess point AP A changes the connection destination of the stationSTA2.

When the connection destination is determined in this manner, as shownwith an arrow Q47, the access point AP A transmits a trigger frame thatinduces transmission of an association request frame (AssociationRequest), which is a connection request signal, to the station STA2, theconnection destination of which is changed, as a destination of thetrigger frame.

It should be noted that hereinafter the trigger frame that inducestransmission of an association request frame is also particularlyreferred to as “association trigger frame”.

This association trigger frame is a connection request inducing signalthat gives an instruction on transmission of an association requestframe, which is a connection request signal requesting connection to anaccess point that has been determined as a new connection destination.

In the example shown in FIG. 6, type information included in theassociation trigger frame is information indicating an associationrequest frame, and sender information is information indicating thestation STA2. Moreover, the association trigger frame includes, asconnection destination information, information indicating a connectiondestination, in other words, information indicating a transmissiondestination (destination) of the association request frame. Inparticular, in this example, the connection destination information isinformation indicating the access point AP B.

Such an association trigger frame is a signal that prompts the stationSTA2 to reconnect to the access point AP B, and thus the access point APA is capable of managing connection of a station by using theassociation trigger frame. In other words, the access point AP A iscapable of designating a connection destination of a station by usingthe association trigger frame.

It should be noted that in the timing shown with the arrow Q47,concurrently with the transmission of the association trigger frame bythe access point AP A, the access point AP A may transmit beforehand, tothe access point AP B that serves as a new connection destination of thestation STA2, a signal indicating that the access point AP B has beendetermined as the connection destination of the station STA2, andindicating a reason for the determination and the like.

Besides the above, before the access point AP A transmits theassociation trigger frame, the access point AP A may communicate withthe access point AP B beforehand to negotiate with the access point AP Bas to whether or not to change the connection destination of the stationSTA2.

When the station STA2 receives the association trigger frame includingsuch connection destination information, as shown with an arrow Q48, thestation STA2 generates an association request frame in response to theassociation trigger frame, and then transmits the association requestframe to the access point AP B. This association request frame is aconnection request signal indicating that the access point AP Bindicated by connection destination information is designated as adestination, and accordingly requesting connection to the access pointAP B.

When the access point AP B receives the association request frametransmitted from the station STA2 as shown with an arrow

Q49, the access point AP B performs association processing (Association)according to the association request frame.

For example, in the association processing, after the station STA2 isauthenticated as necessary, the access point AP B transmits anassociation response frame (Association Response), which is a responseindicating that connection is permitted, to the station STA2.

As the result of such association processing, the connection destinationof the station STA2 has been changed from the access point AP A to theaccess point AP B.

As the result, for example, the packet sequence shown on the lower sideof FIG. 2 is executed, and consequently frequency resources can be moreeffectively utilized.

As described above, by introducing the mechanism described withreference to FIGS. 6 to 8, only changing an access point, or onlyperforming software extension of a station, enables handover betweenaccess points to be easily realized. In other words, connection of eachstation to an appropriate access point is realized, and therebyfrequency resources can be effectively utilized.

Configuration Example of Wireless Communication Device

Subsequently, a specific configuration example of a wirelesscommunication device corresponding to the access point AP A, the accesspoint AP B, the station STA1, and the station STA2 described above willbe described.

FIG. 9 is a diagram illustrating a configuration example of a wirelesscommunication device to which the present technology is applied.

A wireless communication device 11 shown in FIG. 9 functions as anaccess point or a station that wirelessly communicates with otherwireless communication devices.

The wireless communication device 11 includes antennas 21-1 to 21-n, awireless communication module 22, and a data processing unit 23.

The antennas 21-1 to 21-n each wirelessly transmit various kinds ofsignals (frames) supplied from the wireless communication module 22.

In addition, the antennas 21-1 to 21-n each receive a signal (frame)that has been wirelessly transmitted, and each supply the signal to thewireless communication module 22.

It should be noted that hereinafter, in a case where it is notparticularly necessary to distinguish among the antennas 21-1 to 21-n,the antennas 21-1 to 21-n are also merely referred to as “antenna 21”.

The wireless communication module 22 includes, for example, asemiconductor chip and the like, and while giving/receiving informationto/from the data processing unit 23, the wireless communication module22 supplies various kinds of signals (frames) to the antenna 21 to causethe antenna 21 to transmit the signals, and performs processingcorresponding to a signal received by the antenna 21, as appropriate.

The data processing unit 23 extracts various information from the signalsupplied from the wireless communication module 22, and supplies theextract information, generated information, or the like to the wirelesscommunication module 22.

In addition, the wireless communication module 22 includes antennasharing units 51-1 to 51-n, RF receiving units 52-1 to 52-n,digital-signal conversion unit 53-1 to 53-n, a signal receiving unit 54,a signal generation unit 55, analog-signal conversion units 56-1 to56-n, RF transmission units 57-1 to 57-n, and a control unit 58.

These components from the antenna sharing unit 51-1 to the control unit58, which constitute the wireless communication module 22, are laminatedon, for example, one semiconductor chip.

The antenna sharing units 51-1 to 51-n are switches, each of whichswitches between transmission and receiving.

In other words, the antenna sharing units 51-1 to 51-n supply signals(frames) supplied from the RF transmission units 57-1 to 57-n to theantennas 21-1 to 21-n respectively, and supply signals (frames) suppliedfrom the antennas 21-1 to 21-n to the RF receiving units 52-1 to 52-nrespectively.

It should be noted that hereinafter, in a case where it is notparticularly necessary to distinguish among the antenna sharing units51-1 to 51-n, the antenna sharing units 51-1 to 51-n are also merelyreferred to as “antenna sharing unit 51”.

The RF receiving units 52-1 to 52-n each include, for example, alow-noise amplifier, an Auto Gain Control (AGC) unit, a frequencyconverter, a filter, and the like; and the RF receiving units 52-1 to52-n receive signals by the antenna 21 through the antenna sharing units51-1 to 51-n respectively.

The RF receiving units 52-1 to 52-n subject the received signals tovarious kinds of processing such as amplification processing, gainadjustment processing, frequency conversion processing, and filterprocessing as appropriate, and then supply signals obtained as theresult thereof to the digital-signal conversion units 53-1 to 53-nrespectively.

In addition, the RF receiving units 52-1 to 52-n also determine, forexample, reception intensities of the received signals, and supply thereception intensities to the control unit 58 respectively, as necessary.

It should be noted that hereinafter, in a case where it is notparticularly necessary to distinguish among the RF receiving units 52-1to 52-n, the RF receiving units 52-1 to 52-n are also merely referred toas “RF receiving unit 52”.

The digital-signal conversion units 53-1 to 53-n handle signals suppliedfrom the RF receiving units 52-1 to 52-n to perform conversion fromanalog signals to digital signals by Analog Digital (AD) conversion, andsupply the digital signals to the signal receiving unit 54.

It should be noted that hereinafter, in a case where it is notparticularly necessary to distinguish among the digital-signalconversion units 53-1 to 53-n, the digital-signal conversion units 53-1to 53-n are also merely referred to as “digital-signal conversion unit53”.

The signal receiving unit 54 subjects the signals supplied from thedigital-signal conversion unit 53 to various kinds of processing such asdemodulation and decoding according to control of the control unit 58,and supplies signals obtained as a result thereof to the control unit58.

The control unit 58 controls operation of the wireless communicationdevice 11 as a whole. For example, the control unit 58 supplies a signalsupplied from the signal receiving unit 54 to the data processing unit23, and supplies information supplied from the data processing unit 23to the signal generation unit 55.

The signal generation unit 55 performs encoding processing or the likeon the basis of information or the like supplied from the control unit58 to generate a signal in a predetermined format, then subjects thegenerated signal to modulation processing, and subsequently supplies themodulated signal to the analog-signal conversion units 56-1 to 56-n.

The analog-signal conversion units 56-1 to 56-n handle signals suppliedfrom the signal generation unit 55 to perform conversion from digitalsignals to analog signals by Digital Analog (DA) conversion, and supplythe converted signals to the RF transmission units 57-1 to 57-n.

It should be noted that hereinafter, in a case where it is notparticularly necessary to distinguish among the analog-signal conversionunits 56-1 to 56-n, the analog-signal conversion units 56-1 to 56-n arealso merely referred to as “analog-signal conversion unit 56”.

The RF transmission units 57-1 to 57-n each include, for example, afrequency converter, an amplifier, a filter, and the like. The RFtransmission units 57-1 to 57-n subject signals supplied from theanalog-signal conversion units 56-1 to 56-n to frequency conversionprocessing, amplification processing, filter processing, and the like,and then supply the signals to the antenna 21-1 to 21-n through theantenna sharing units 51-1 to 51-n so as to cause the antenna 21-1 to21-n to transmit the signals.

It should be noted that hereinafter, in a case where it is notparticularly necessary to distinguish among the RF transmission units57-1 to 57-n, the RF transmission units 57-1 to 57-n are also merelyreferred to as “RF transmission unit 57”.

About Connection-Destination Determination Processing

Next, operation of the wireless communication device 11 shown in FIG. 9will be described.

First of all, connection-destination determination processing in whichthe wireless communication device 11 that is an access point optimizesconnection destinations of stations under the control of the wirelesscommunication device 11 itself will be described.

In other words, connection-destination determination processingperformed by the wireless communication device 11 will be describedbelow with reference to a flowchart shown in FIG. 10. It should be notedthat in this case, the wireless communication device 11 corresponds tothe access point AP A described with reference to FIG. 6.

In step S11, the RF transmission unit 57 transmits a measurement requestframe by using the antenna 21.

In other words, the control unit 58 supplies sender informationindicating each station under the control of the wireless communicationdevice 11, received power information, resource information, typeinformation, trigger delay amount information, and the like to thesignal generation unit 55, and gives an instruction on generation of themeasurement request frame.

Consequently, on the basis of the sender information, the received powerinformation, the resource information, the type information, the triggerdelay amount information, and the like, which have been supplied fromthe control unit 58, the signal generation unit 55 generates ameasurement request frame having a configuration shown in FIG. 7. Atthis point, a trigger body of the measurement request frame is adaptedto include, for example, a trigger frame as it is, the trigger framebeing transmitted in the undermentioned step S12.

In addition, the signal generation unit 55 subjects the generatedmeasurement request frame to modulation processing and the like, andthen supplies the modulated measurement request frame to theanalog-signal conversion unit 56.

The analog-signal conversion unit 56 subjects the measurement requestframe supplied from the signal generation unit 55 to digital-to-analogconversion, and then supplies the converted measurement request frame tothe RF transmission unit 57. The RF transmission unit 57 subjects themeasurement request frame supplied from the analog-signal conversionunit 56 to frequency conversion processing, amplification processing,filter processing, and the like as appropriate, and then outputs themeasurement request frame to the antenna 21 through the antenna sharingunit 51 so as to transmit the measurement request frame.

In step S12, the RF transmission unit 57 transmits a trigger frame byusing the antenna 21.

In other words, the control unit 58 supplies sender informationindicating each station under the control of the wireless communicationdevice 11, received power information, resource information, typeinformation, and the like to the signal generation unit 55, and gives aninstruction on generation of a trigger frame.

Consequently, on the basis of the sender information, the received powerinformation, the resource information, the type information, and thelike, which have been supplied from the control unit 58, the signalgeneration unit 55 generates a trigger frame having a configurationshown in FIG. 3. Subsequently, the signal generation unit 55 subjectsthe generated trigger frame to modulation processing and the like, andsupplies the trigger frame to the RF transmission unit 57 through theanalog-signal conversion unit 56.

The RF transmission unit 57 subjects the trigger frame supplied from theanalog-signal conversion unit 56 to frequency conversion processing andthe like as appropriate, and then outputs the trigger frame to theantenna 21 through the antenna sharing unit 51 so as to transmit thetrigger frame.

When the trigger frame is transmitted in this manner, a station that hasreceived the trigger frame transmits a trigger response frame, andtherefore the wireless communication device 11 receives the triggerresponse frame.

In other words, the RF receiving unit 52 receives the trigger responseframe through the antenna sharing unit 51 and the antenna 21, andsupplies the received trigger response frame to the control unit 58through the digital-signal conversion unit 53 and the signal receivingunit 54.

In step S13, the wireless communication device 11 grasps a propagationstatus of a signal (frame) in the wireless communication device 11's ownBSS. In other words, in step S13, measurement processing is performed,and distance indicator information that is information related to arelative distance between the wireless communication device 11 and thestation is generated. Here, processing similar to that in step S83 ofFIG. 12 described below is performed as the measurement processing.

For example, the RF receiving unit 52 determines reception intensity ofthe trigger response frame on the basis of the received trigger responseframe, and supplies the obtained reception intensity to the control unit58 as distance indicator information. In this case, the RF receivingunit 52 functions as a measurement unit that performs measurementprocessing.

It should be noted that when a plurality of stations exists under thecontrol of the wireless communication device 11, the RF receiving unit52 receives trigger response frames transmitted from those stations.However, since resources used to transmit those trigger response framesdiffer from each other, the RF receiving unit 52 is capable of obtainingreception intensity on a trigger response frame basis by separating theplurality of trigger response frames.

Besides the above, for example, the RF receiving unit 52 may generatethe reception time of the trigger response frame as distance indicatorinformation, or may generate the time (delay amount) from thetransmission time to the reception time of the trigger response frame asdistance indicator information. In addition, the RF receiving unit 52may generate the time (delay amount) from the transmission time of themeasurement request frame to the reception time of the trigger responseframe as distance indicator information. In these cases, the RFreceiving unit 52 functions as a measurement unit that performsmeasurement processing.

Moreover, the data processing unit 23 may generate a receiving errorrate of the trigger response frame, in other words, an error property,as distance indicator information. In this case, the data processingunit 23 functions as the measurement unit that performs measurementprocessing.

In a case where the receiving error rate is generated as distanceindicator information, the control unit 58 supplies the trigger responseframe supplied from the signal receiving unit 54 to the data processingunit 23, and causes the data processing unit 23 to calculate thereceiving error rate.

On the basis of a frame check sequence included in the trigger responseframe supplied from the control unit 58, the data processing unit 23performs computation for checking whether or not the trigger responseframe has been correctly received, and calculates the receiving errorrate from the computation result.

The receiving error rate obtained in this manner is obtained from thedata processing unit 23 as distance indicator information by the controlunit 58.

The distance indicator information including the reception intensity,the reception time, and the receiving error rate such as those describedabove is information that serves as an indicator indicating a distancefrom an access point to a station. However, it can also be said that thedistance indicator information is information indicating a propagationstatus of the trigger response frame that has been given/receivedbetween the access point and the station. This is because it can be saidthat, for example, when reception intensity is sufficiently large, orwhen a receiving error rate is low, a propagation status of a triggerresponse frame is excellent.

In addition, when a trigger response frame is transmitted by a station,an access point that has received the trigger response frame and themeasurement request frame transmits a measurement response frame inresponse to the measurement request frame.

In step S14, the RF receiving unit 52 receives the measurement responseframe through the antenna sharing unit 51 and the antenna 21, andsupplies the measurement response frame to the control unit 58 throughthe digital-signal conversion unit 53 and the signal receiving unit 54.Consequently, the measurement response frame having the configurationshown in, for example, FIG. 8 is received.

In step S15, the control unit 58 causes identification information anddistance indicator information to be read from the measurement responseframe.

In other words, the control unit 58 supplies the measurement responseframe, which has been supplied from the signal receiving unit 54, to thedata processing unit 23, and instructs the data processing unit 23 toread the identification information and the distance indicatorinformation from the measurement response frame.

Consequently, the data processing unit 23 reads one set ofidentification information and distance indicator information from themeasurement response frame, and then supplies the set to the controlunit 58.

It can be said that the distance indicator information that has beenread in this manner is information indicating an indicator of a distancebetween an access point and a station, in other words, informationindicating a propagation status of a signal between the access point andthe station.

In step S16, the control unit 58 compares the propagation status graspedin step S13 with the propagation status identified by the distanceindicator information that has been read in step S15.

In other words, the control unit 58 treats a station, which is indicatedby the identification information read in step S15, as a station that isa processing target, and for the station, the control unit 58 comparesthe distance indicator information obtained in step S13 with thedistance indicator information read in step S15.

As the result, positional relationship among the wireless communicationdevice 11, an access point that is a sender of a measurement responseframe, and a station that is a processing target is identified. In otherwords, which is a more excellent propagation status is identified frombetween: a propagation status of a signal between the wirelesscommunication device 11 and a station that is a processing target; and apropagation status of a signal between an access point that is a senderof the measurement response frame and a station that is a processingtarget.

In step S17, on the basis of a result of the comparison in step S16, thecontrol unit 58 decides whether or not to change a connectiondestination of the station that is the processing target.

For example, in step S17, as the result of the comparison of distanceindicator information, in a case where the station that is theprocessing target is located at a position nearer to the access pointthat is the sender of the measurement response frame than the wirelesscommunication device 11, it is decided that the connection destinationneeds to be changed.

In other words, in a case where a propagation status of a signal betweenthe access point that is the sender of the measurement response frameand the station that is the processing target is more excellent than apropagation status of a signal between the wireless communication device11 and the station that is the processing target, it is decided thathandover of the connection destination is performed for the station thatis the processing target. In addition, in a case where the connectiondestination of the station that is the processing target is changed, thecontrol unit 58 also determines an access point that serves as a newconnection destination of the station that is the processing target.

By deciding whether or not to change a connection destination in thismanner, it can be said that the control unit 58 that performsoptimization of connection destinations of stations under controlfunctions as a determining unit that determines a connection destinationof a station on the basis of a propagation status of a signal.

In a case where it has been decided, in step S17, that the connectiondestination does not need to be changed, the process then proceeds tostep S19.

Meanwhile, in a case where it has been decided, in step S17, that theconnection destination needs to be changed, the process proceeds to stepS18. In step S18, the control unit 58 adds a station that is aprocessing target, and information indicating a new connectiondestination of the station, to a handover list that is a list ofstations, each of which requires handover. When the handover list isupdated in this manner, the process then proceeds to step S19.

It should be noted that the control unit 58 resets the handover list atthe time of starting the connection-destination determinationprocessing, and updates the maintained handover list every timeprocessing of step S18 is performed.

In a case where the processing of step S18 has been performed, or in acase where it has been decided, in step S17, that the connectiondestination does not need to be changed, processing of step S19 isperformed.

In step S19, the control unit 58 decides whether or not identificationinformation and distance indicator information have been all read fromthe measurement response frame.

In step S19, in a case where it has been decided that the identificationinformation and the distance indicator information have not yet been allread, the process returns to step S15, and the above-describedprocessing is repeatedly performed.

Meanwhile, in a case where it has been decided, in step S19, that theidentification information and the distance indicator information havebeen all read, a decision as to whether or not to change a connectiondestination has been made for all stations under control, and thereforethe process then proceeds to step S20.

In step S20, on the basis of the maintained handover list, the controlunit 58 decides whether or not there is a station, the connectiondestination of which needs to be changed.

For example, in a case where the handover list includes informationindicating a station, it is decided, in step S20, that there is astation, the connection destination of which needs to be changed.

In a case where it has been decided, in step S20, that there is nostation, the connection destination of which needs to be changed, change(handover) of a connection destination of a station under the control ofthe wireless communication device 11 is not performed, and theconnection-destination determination processing ends. In this case, itcan be said that the optimum connection destination of the station underthe control of the wireless communication device 11 has been thewireless communication device 11.

Meanwhile, in a case where it has been decided, in step S20, that thereis a station, the connection destination of which needs to be changed,the RF transmission unit 57 transmits an association trigger frame byusing the antenna 21 in step S21.

For example, for a station, the connection destination of which needs tobe changed, indicated by information included in the handover list, thecontrol unit 58 instructs the signal generation unit 55 to generate anassociation trigger frame.

At this point, with respect to the station, the connection destinationof which needs to be changed, the control unit 58 also supplies thesignal generation unit 55 with, for example, sender information,resource information, received power information, type informationindicating an association request frame, and connection destinationinformation indicating an access point that is a connection destination.

The signal generation unit 55 generates an association trigger framethat includes, for example, the sender information, the resourceinformation, the received power information, the type information, andthe connection destination information, which have been supplied fromthe control unit 58. Subsequently, the signal generation unit 55subjects the generated association trigger frame to modulationprocessing and the like, and supplies the association trigger frame tothe RF transmission unit 57 through the analog-signal conversion unit56.

The RF transmission unit 57 subjects the association trigger framesupplied from the analog-signal conversion unit 56 to frequencyconversion processing and the like as appropriate, and then outputs theassociation trigger frame to the antenna 21 through the antenna sharingunit 51 so as to transmit the association trigger frame.

When the association trigger frame is transmitted, theconnection-destination determination processing ends. It should be notedthat when the association trigger frame is transmitted, a signal relatedto association is then transmitted/received between the station and theaccess point indicated by the connection destination information, andconsequently the connection destination of the station is changed.

As described above, the wireless communication device 11 transmits ameasurement request frame, and receives a measurement response frametransmitted in response thereto. Subsequently, on the basis of thereceived measurement response frame, the wireless communication device11 decides whether or not to change a connection destination of astation under control, and thereby optimizes connection destinations.

Performing the above processing in such a manner enables the wirelesscommunication device 11, which is an access point, to take theinitiative in determining an appropriate connection destination as aconnection destination of a station, and therefore frequency resourcescan be more effectively utilized.

About Connection-Destination Changing Processing

Next, operation of the wireless communication device 11 functioning as astation that receives a trigger frame transmitted inconnection-destination determination processing of FIG. 10 will bedescribed. In other words, connection-destination changing processingperformed by the wireless communication device 11 will be describedbelow with reference to a flowchart shown in FIG. 11. In this case, thewireless communication device 11 corresponds to the station STA1 and thestation STA2 described with reference to FIG. 6.

In step S51, the RF receiving unit 52 receives a trigger frame throughthe antenna sharing unit 51 and the antenna 21, and supplies the triggerframe to the control unit 58 through the digital-signal conversion unit53 and the signal receiving unit 54. Consequently, a trigger frame thathas been transmitted in, for example, step S12 of FIG. 10 is received,the trigger frame having a configuration shown in FIG. 3.

From sender information and type information included in the triggerframe supplied from the signal receiving unit 54, the control unit 58 iscapable of grasping that the wireless communication device 11 isinstructed to transmit a trigger response frame.

The control unit 58 supplies required information to the signalgeneration unit 55, and instructs the signal generation unit 55 togenerate a trigger response frame, as appropriate. Consequently, thesignal generation unit 55 generates the trigger response frame accordingto the instruction of the control unit 58, subjects the trigger responseframe to modulation processing and the like, and supplies the triggerresponse frame to the RF transmission unit 57 through the analog-signalconversion unit 56.

At this point, the signal generation unit 55 generates a triggerresponse frame in such a manner that the trigger response frame istransmitted by using a frequency resource and a space resource indicatedby resource information included in the trigger frame.

In step S52, the RF transmission unit 57 transmits a trigger responseframe supplied from the analog-signal conversion unit 56 by using theantenna 21.

In other words, the RF transmission unit 57 subjects the triggerresponse frame supplied from the analog-signal conversion unit 56 tofrequency conversion processing and the like as appropriate, and thenoutputs the trigger response frame to the antenna 21 through the antennasharing unit 51 so as to transmit the trigger response frame.

At this point, the control unit 58 controls transmission performed bythe RF transmission unit 57 in such a manner that a trigger responseframe is transmitted by transmission power defined by trigger frametransmission power information and received power information, which areincluded in the trigger frame received in step S51. It should be notedthat in more detail, the transmission power for transmitting the triggerresponse frame is defined on the basis of trigger frame transmissionpower information, received power information, and received power at thetime of receiving the trigger frame.

The trigger response frame that has been transmitted in this manner isreceived by the access point that is the connection destination of thewireless communication device 11, and is used for processing in step S13of FIG. 10, or is received in step S82 of FIG. 12 described later, stepS82 being executed by an access point that is not a connectiondestination of the wireless communication device 11.

In addition, when a trigger response frame is transmitted, anassociation trigger frame is then transmitted from an access point thatserves as a connection destination as necessary. In other words, in acase where the connection destination of the wireless communicationdevice 11 is changed, an association trigger frame is transmitted froman access point.

In step S53, the control unit 58 decides whether or not to change theconnection destination of the wireless communication device 11. In otherwords, in step S53, in a case where an association trigger frame hasbeen transmitted to the wireless communication device 11, it is decidedthat the connection destination needs to be changed.

In a case where it has been decided, in step S53, that the connectiondestination does not need to be changed, the connection-destinationchanging processing ends without executing processing of step S54 andprocessing of step S55.

Meanwhile, in a case where it has been decided that the connectiondestination needs to be changed, the process then proceeds to step S54.

In step S54, the RF receiving unit 52 receives the association triggerframe through the antenna sharing unit 51 and the antenna 21, andsupplies the association trigger frame to the control unit 58 throughthe digital-signal conversion unit 53 and the signal receiving unit 54.This association trigger frame has been transmitted by processing instep S21 of FIG. 10 by using an access point that is a connectiondestination of the wireless communication device 11 at the present pointof time.

When the association trigger frame is supplied from the signal receivingunit 54, the control unit 58 instructs the signal generation unit 55 togenerate an association request frame that requests connection to anaccess point indicated by connection destination information included inthe association trigger frame. At this point, the control unit 58supplies required information including connection destinationinformation and the like to the signal generation unit 55.

The signal generation unit 55 generates an association request frame onthe basis of, for example, the connection destination informationsupplied from the control unit 58, subjects the association requestframe to modulation processing and the like, and then supplies theassociation request frame to the RF transmission unit 57 through theanalog-signal conversion unit 56.

In step S55, the RF transmission unit 57 transmits the associationrequest frame by using the antenna 21.

In other words, the RF transmission unit 57 subjects the associationrequest frame supplied from the analog-signal conversion unit 56 tofrequency conversion processing and the like as appropriate, and thenoutputs the association request frame to the antenna 21 through theantenna sharing unit 51 so as to transmit the association request frame.

When the association request frame is transmitted, a signal related toassociation is then transmitted/received between the wirelesscommunication device 11 and the access point indicated by the connectiondestination information, and consequently the connection destination ofthe wireless communication device 11 is changed. Subsequently, when theconnection destination of the wireless communication device 11 ischanged, the connection-destination changing processing ends.

As described above, the wireless communication device 11 transmits atrigger response frame in response to a received trigger frame, and whenan association trigger frame is received, the wireless communicationdevice 11 transmits an association request frame in response thereto,and changes a connection destination.

By performing the processing in such a manner, the wirelesscommunication device 11 is capable of connecting to an appropriateconnection destination on the basis of control by an access point.Consequently, frequency resources can be more effectively utilized.

About Response Processing

Moreover, operation of the wireless communication device 11 functioningas an access point that receives a measurement request frame transmittedin the connection-destination determination processing of FIG. 10 willbe described. In other words, response processing performed by thewireless communication device 11 will be described below with referenceto a flowchart shown in FIG. 12. In this case, the wirelesscommunication device 11 corresponds to the access point AP B describedwith reference to FIG. 6.

In step S81, the RF receiving unit 52 receives a measurement requestframe through the antenna sharing unit 51 and the antenna 21, andsupplies the measurement request frame to the control unit 58 throughthe digital-signal conversion unit 53 and the signal receiving unit 54.Consequently, a measurement request frame that has been transmitted in,for example, step S11 of FIG. 10 is received, the measurement requestframe having a configuration shown in FIG. 7.

The measurement request frame is received, and subsequently, processingin step S52 of FIG. 11 is performed after the lapse of time defined bytrigger delay amount information included in the measurement requestframe, and consequently a trigger response frame is transmitted.

In step S82, the RF receiving unit 52 receives a trigger response framethrough the antenna sharing unit 51 and the antenna 21, and supplies thetrigger response frame to the control unit 58 through the digital-signalconversion unit 53 and the signal receiving unit 54.

It should be noted that in step S82, trigger response frames transmittedfrom one or a plurality of stations are received. As described above,trigger response frames transmitted from respective stations differ inat least one of a frequency resource or a space resource used at thetime of transmission, and therefore the wireless communication device 11is capable of separating the plurality of trigger response frames.

In step S83, on a received trigger response frame basis, that is to say,on a station basis, the wireless communication device 11 performsmeasurement processing for obtaining distance indicator informationindicating an indicator of a relative distance between the wirelesscommunication device 11 and a station.

In other words, on the basis of the receiving timing of the triggerresponse frame, or on the basis of the received trigger response frame,measurement processing for obtaining distance indicator informationindicating a propagation status of a signal between the wirelesscommunication device 11 and a station is performed.

For example, the RF receiving unit 52 determines reception intensity ofthe trigger response frame on the basis of the received trigger responseframe, and supplies the obtained reception intensity to the control unit58 as distance indicator information. In this case, the RF receivingunit 52 functions as a measurement unit that measures receptionintensity of the trigger response frame as measurement processingrelated to a propagation status of a signal.

Besides the above, for example, the RF receiving unit 52 may generatethe reception time of the trigger response frame as distance indicatorinformation, or may generate the time (delay amount) from thetransmission time of the trigger response frame to the reception time ofthe trigger response frame as distance indicator information. Inaddition, for example, the RF receiving unit 52 may generate the time(delay amount) from the reception time of the measurement request frameto the reception time of the trigger response frame as distanceindicator information. In these cases, the RF receiving unit 52functions as a measurement unit that measures the reception time and thedelay amount on the basis of the receiving timing of the triggerresponse frame as measurement processing.

Moreover, for example, the data processing unit 23 may generate areceiving error rate of the trigger response frame as distance indicatorinformation.

In a case where the receiving error rate is generated as distanceindicator information, the control unit 58 supplies the trigger responseframe supplied from the signal receiving unit 54 to the data processingunit 23, and causes the data processing unit 23 to calculate thereceiving error rate.

On the basis of a frame check sequence included in the trigger responseframe supplied from the control unit 58, the data processing unit 23performs computation for checking whether or not the trigger responseframe has been correctly received, and calculates the receiving errorrate from the computation result.

The receiving error rate obtained in this manner is obtained from thedata processing unit 23 as distance indicator information by the controlunit 58. In this case, the data processing unit 23 functions as ameasurement unit that measures a receiving error rate, that is to say,an error property, on the basis of the trigger response frame asmeasurement processing related to a propagation status of a signal.

The control unit 58 supplies distance indicator information obtained inthis manner, and identification information corresponding to thedistance indicator information, to the signal generation unit 55, andinstructs the signal generation unit 55 to generate a measurementresponse frame.

Here, for example, sender information included in a trigger body of themeasurement request frame received in step S81 may be used asidentification information, or resource information included in thetrigger body may be used as identification information.

In step S84, the signal generation unit 55 generates a measurementresponse frame on the basis of the distance indicator information andthe identification information supplied from the control unit 58.Consequently, the measurement response frame having the configurationshown in, for example, FIG. 8 is generated.

In addition, the signal generation unit 55 subjects the generatedmeasurement response frame to modulation processing and the like, andsupplies the measurement response frame to the RF transmission unit 57through the analog-signal conversion unit 56.

In step S85, the RF transmission unit 57 transmits the measurementresponse frame supplied from the analog-signal conversion unit 56 byusing the antenna 21.

In other words, the RF transmission unit 57 subjects the measurementresponse frame supplied from the analog-signal conversion unit 56 tofrequency conversion processing and the like as appropriate, and thenoutputs the measurement response frame to the antenna 21 through theantenna sharing unit 51 so as to transmit the measurement responseframe.

The measurement response frame that has been transmitted in this manneris received by the processing in step S14 of FIG. 10 by using an accesspoint that is a sender of the measurement request frame.

Consequently, the access point that is the sender of the measurementrequest frame transmits an association trigger frame as appropriate, andtherefore a station that has received the association trigger frametransmits an association request frame to the wireless communicationdevice 11. This association request frame is the one that has beentransmitted by the processing in step S55 of FIG. 11.

In step S86, the RF receiving unit 52 receives the association requestframe through the antenna sharing unit 51 and the antenna 21, andsupplies the association request frame to the control unit 58 throughthe digital-signal conversion unit 53 and the signal receiving unit 54.

In step S87, the wireless communication device 11 performs associationprocessing according to the received association request frame.

For example, in the association processing, necessary processing such asauthentication is performed between the wireless communication device 11and a station.

In addition, when association (connection) of the station is permitted,then according to control of the control unit 58, the signal generationunit 55 generates an association response frame indicating thatconnection is permitted, and supplies the association response frame tothe RF transmission unit 57 through the analog-signal conversion unit56. Moreover, the RF transmission unit 57 outputs an associationresponse frame, which has been supplied from the analog-signalconversion unit 56, to the antenna 21 through the antenna sharing unit51, thereby transmitting the association response frame to the station,and consequently connection to the station is established.

The association processing is performed in this manner, and subsequentlythe response processing ends. It should be noted that in a case wherethere is no station, the new connection destination of which is thewireless communication device 11, for example, in a case where it hasbeen decided, in step S20 of FIG. 10, that there is no station, theconnection destination of which needs to be changed, the processing instep S86 and that in step S87 are not executed.

In a manner described above, the wireless communication device 11performs measurement processing according to the received measurementrequest frame, and transmits the measurement response frame thatincludes a measurement result thereof. By performing the processing insuch a manner, the wireless communication device 11 is capable ofcooperating with other access points to cause a station around thewireless communication device 11 to connect to an appropriate connectiondestination, and consequently frequency resources can be moreeffectively utilized.

Configuration Example of Computer

Incidentally, the series of processing described above can be executedby hardware, and can also be executed by software. In a case where theseries of processing is executed by software, a program that configuresthe software is installed in a computer. Here, the computer includes acomputer that is built into dedicated hardware, and a computer that iscapable of executing various kinds of functions by installing variouskinds of programs, for example, a general-purpose personal computer andthe like.

FIG. 13 is a block diagram illustrating a configuration example ofhardware of a computer that executes the above-described series ofprocessing by a program.

In the computer, a central processing unit (CPU) 501, a Read Only Memory(ROM) 502, and a random access memory (RAM) 503 are mutually connectedthrough a bus 504.

An input-output interface 505 is further connected to the bus 504. Aninput unit 506, an output unit 507, a recording unit 508, acommunication unit 509, and a drive 510 are connected to theinput-output interface 505.

The input unit 506 includes a keyboard, a mouse, a microphone, an imagepickup element, and the like. The output unit 507 includes a display, aspeaker, and the like. The recording unit 508 includes a hard disk, anonvolatile memory, and the like. The communication unit 509 includes anantenna, a network interface, and the like. The drive 510 drives aremovable recording medium 511 such as a magnetic disk, an optical disk,a magneto-optical disk, or a semiconductor memory.

In the computer that is configured as described above, the CPU 501loads, for example, a program stored in the recording unit 508 into theRAM 503 through the input-output interface 505 and the bus 504, thenexecutes the program, and consequently the above-described series ofprocessing is performed.

The program executed by the computer (CPU 501) can be provided by beingrecorded, for example, in a removable recording medium 511 such as apackage media. In addition, the program can be provided through a wiredor wireless transmission medium such as a local area network, theInternet, and digital satellite broadcasting.

In the computer, the program can be installed in the recording unit 508through the input-output interface 505 by mounting the removablerecording medium 511 to the drive 510. In addition, the program can bereceived by the communication unit 509 through a wired or wirelesstransmission medium, and can be installed in the recording unit 508.Besides the above, the program can be installed in the ROM 502 or therecording unit 508 beforehand.

It should be noted that the program executed by the computer may be aprogram in which processing is time-sequentially performed along theorder described in the present description, or may be a program in whichprocessing is performed in parallel or in the required timing, forexample, when a call is made.

In addition, embodiments of the present technology are not limited tothe embodiments described above. Various modifications can be madewithin the scope that does not deviate from the gist of the presenttechnology.

For example, the present technology can be configured as cloud computingin which one function is processed by being shared by a plurality ofdevices in cooperation through a network.

Further, each step explained in the above-described flowchart isexecuted by one device. Alternatively, the each step can be executed bybeing shared by a plurality of devices.

Furthermore, in a case where one step includes a plurality of pieces ofprocessing, the plurality of pieces of processing included in the onestep is executed by one device.

Alternatively, the plurality of pieces of processing can be executed bybeing shared by a plurality of devices.

Moreover, the present technology may have the following configuration.

(1)

A wireless communication device connected to one or a plurality oftarget wireless communication devices, the wireless communication deviceincluding:

a transmission unit that transmits, to another wireless communicationdevice, a measurement request signal requesting measurement related to apropagation status of a signal from the target wireless communicationdevice; and

a receiving unit that receives a measurement request response signaltransmitted from the another wireless communication device in responseto the measurement request signal, the measurement request responsesignal including a result of the measurement.

(2)

The wireless communication device set forth in (1), further including

a determining unit that determines a connection destination of thetarget wireless communication device on the basis of the result of themeasurement, in which

the determining unit determines a connection destination of the targetwireless communication device by comparing a propagation status of asignal between the wireless communication device and the target wirelesscommunication device with a propagation status of a signal between theanother wireless communication device and the target wirelesscommunication device, the latter propagation status being indicated bythe result of the measurement.

(3)

The wireless communication device set forth in (2), in which:

the transmission unit further transmits, to the target wirelesscommunication device, a transmission request signal that gives aninstruction on transmission of a response signal for the measurement;and

the receiving unit receives, from the another wireless communicationdevice, the measurement request response signal including the result ofthe measurement performed by receiving the response signal transmittedfrom the target wireless communication device.

(4)

The wireless communication device set forth in (3), in which

the measurement request signal includes information used to identify thetarget wireless communication device that transmits the response signal.

(5)

The wireless communication device set forth in (3) or (4), in which:

the receiving unit receives the response signal transmitted from thetarget wireless communication device; and

the determining unit compares a propagation status of a signal betweenthe wireless communication device and the target wireless communicationdevice, the propagation status having been obtained by receiving theresponse signal, with a propagation status of a signal between theanother wireless communication device and the target wirelesscommunication device.

(6)

The wireless communication device set forth in any one of (3) to (5), inwhich

the transmission request signal includes a trigger frame defined by IEE802.11ax.

(7)

The wireless communication device set forth in any one of (3) to (6), inwhich

the determining unit compares distance indicator information that servesas an indicator of a distance to the target wireless communicationdevice as a propagation status.

(8)

The wireless communication device set forth in (7), in which

the distance indicator information includes reception intensity of theresponse signal, reception time of the response signal, time fromtransmission time of the response signal to reception time of theresponse signal, or an error property at the time of receiving of theresponse signal.

(9)

The wireless communication device set forth in (8), in which

the measurement request signal includes information used to identifytransmission timing of the response signal.

(10)

The wireless communication device set forth in any one of (1) to (9), inwhich

the transmission unit transmits, to the target wireless communicationdevice, a connection request inducing signal that gives an instructionon transmission of a connection request signal requesting connection tothe another wireless communication device that has been determined as anew connection destination of the target wireless communication device.

(11)

A wireless communication method performed by a wireless communicationdevice connected to one or a plurality of target wireless communicationdevices, the wireless communication method including the steps of:

transmitting, to another wireless communication device, a measurementrequest signal requesting measurement related to a propagation status ofa signal from the target wireless communication device; and

receiving a measurement request response signal transmitted from theanother wireless communication device in response to the measurementrequest signal, the measurement request response signal including aresult of the measurement.

(12)

A wireless communication device including:

a receiving unit that, with respect to one or a plurality of targetwireless communication devices connected to another wirelesscommunication device, receives a measurement request signal requestingmeasurement related to a propagation status of a signal from the targetwireless communication device, the measurement request signal havingbeen transmitted from the another wireless communication device;

a signal generation unit that, in response to the measurement requestsignal, generates a measurement request response signal including aresult of the measurement related to the propagation status of thesignal from the target wireless communication device; and

a transmission unit that transmits the measurement request responsesignal to the another wireless communication device.

(13)

The wireless communication device set forth in (12), in which:

the another wireless communication device transmits a transmissionrequest signal that gives an instruction on transmission of a responsesignal for the measurement, and consequently the receiving unit furtherreceives the response signal transmitted from the target wirelesscommunication device in response to the transmission request signal; and

the signal generation unit generates the measurement request responsesignal including a result of the measurement obtained by receiving theresponse signal.

(14)

The wireless communication device set forth in (13), in which:

the measurement request signal includes information used to identify thetarget wireless communication device that transmits the response signal;and

the signal generation unit generates the measurement request responsesignal including identification information identifying the targetwireless communication device that is a sender of the response signal,and including a result of the measurement obtained with respect to thetarget wireless communication device identified by the identificationinformation.

(15)

The wireless communication device set forth in (13) or (14), in which

the transmission request signal includes a trigger frame defined by IEE802.11ax.

(16)

The wireless communication device set forth in any one of (13) to (15),in which

the result of the measurement includes distance indicator informationthat serves as an indicator of a distance to the target wirelesscommunication device.

(17)

The wireless communication device set forth in (16), further including

a measurement unit that performs the measurement on the basis ofreceiving timing of the response signal or the received response signal.

(18)

The wireless communication device set forth in (16) or (17), in which

the distance indicator information includes reception intensity of theresponse signal, reception time of the response signal, time fromtransmission time of the response signal to reception time of theresponse signal, or an error property at the time of receiving of theresponse signal.

(19)

The wireless communication device set forth in (18), in which

the measurement request signal includes information used to identifytransmission timing of the response signal.

(20)

A wireless communication method performed by a wireless communicationdevice, the wireless communication method including the steps of:

with respect to one or a plurality of target wireless communicationdevices connected to another wireless communication device, receiving ameasurement request signal requesting measurement related to apropagation status of a signal from the target wireless communicationdevice, the measurement request signal having been transmitted from theanother wireless communication device;

in response to the measurement request signal, generating a measurementrequest response signal including a result of the measurement related tothe propagation status of the signal from the target wirelesscommunication device; and

transmitting the measurement request response signal to the anotherwireless communication device.

(21)

A wireless communication device including:

a receiving unit that receives a connection request inducing signal thathas been transmitted from a first wireless communication deviceconnected, and that gives an instruction on transmission of a connectionrequest signal requesting connection to a second wireless communicationdevice determined as its own new connection destination; and

a transmission unit that transmits the connection request signal to thesecond wireless communication device according to the connection requestinducing signal.

(22)

The wireless communication device set forth in (21), in which

the receiving unit receives a transmission request signal that has beentransmitted from the first wireless communication device, and that givesan instruction on transmission of a response signal for measurementrelated to a propagation status of a signal to/from the second wirelesscommunication device, and after the response signal has been transmittedby the transmission unit in response to the transmission request signal,receives the connection request inducing signal transmitted from thefirst wireless communication device.

(23)

The wireless communication device set forth in (22), in which

the second wireless communication device that serves as its own newconnection destination is determined by the first wireless communicationdevice on the basis of a result of the measurement.

(24)

A wireless communication method performed by a wireless communicationdevice, the wireless communication method including the steps of:

receiving a connection request inducing signal that has been transmittedfrom a first wireless communication device connected, and that instructstransmission of a connection request signal requesting connection to asecond wireless communication device determined as its own newconnection destination; and

transmitting the connection request signal to the second wirelesscommunication device according to the connection request inducingsignal.

REFERENCE SIGNS LIST

-   11 Wireless communication device-   21-1 to 21-n, 21 Antenna-   22 Wireless communication module-   23 Data processing unit-   52-1 to 52-n, 52 RF receiving unit-   55 Signal generation unit-   57-1 to 57-n, 57 RF transmission unit-   58 Control unit

The invention claimed is:
 1. A wireless communication device connectedto one or a plurality of target wireless communication devices, thewireless communication device, comprising: a central processing unit(CPU) configured to: transmit, to another wireless communication device,a measurement request signal to request measurement related to a firstpropagation status of a first signal between a target wirelesscommunication device, of the one or the plurality of target wirelesscommunication devices, and the other wireless communication device;receive a measurement request response signal transmitted from the otherwireless communication device based on the transmitted measurementrequest signal, the measurement request response signal including aresult of the measurement; compare a second propagation status of asecond signal between the wireless communication device and the targetwireless communication device, with the first propagation status of thefirst signal between the other wireless communication device and thetarget wireless communication device, the first propagation status beingindicated by the result of the measurement; and determine a connectiondestination of the target wireless communication device based on thecomparison.
 2. The wireless communication device according to claim 1,wherein the CPU is further configured to: transmit, to the targetwireless communication device, a transmission request signal that givesan instruction on transmission of a response signal for the measurement;and receive, from the other wireless communication device, themeasurement request response signal including the result of themeasurement performed based on a reception of the response signaltransmitted from the target wireless communication device.
 3. Thewireless communication device according to claim 2, wherein themeasurement request signal includes information used to identify thetarget wireless communication device that transmits the response signal.4. The wireless communication device according to claim 2, wherein theCPU is further configured to: receive the response signal transmittedfrom the target wireless communication device; and compare the secondpropagation status of the second signal between the wirelesscommunication device and the target wireless communication device, withthe first propagation status of the first signal between the otherwireless communication device and the target wireless communicationdevice, wherein the second propagation status is obtained based on thereception of the response signal.
 5. The wireless communication deviceaccording to claim 2, wherein the transmission request signal includes atrigger frame defined by IEE 802.11ax.
 6. The wireless communicationdevice according to claim 2, wherein the CPU is further configured to:compare distance indicator information that serves as an indicator of adistance between the target wireless communication device and the otherwireless communication device as the first propagation status.
 7. Thewireless communication device according to claim 6, wherein the distanceindicator information includes reception intensity of the responsesignal, reception time of the response signal, time from transmissiontime of the response signal to the reception time of the responsesignal, or an error property at the time of reception of the responsesignal.
 8. The wireless communication device according to claim 7,wherein the measurement request signal includes delay amount informationused to identify transmission timing of the response signal from thetarget wireless communication.
 9. The wireless communication deviceaccording to claim 1, wherein the CPU is further configured to:transmit, to the target wireless communication device, a connectionrequest inducing signal that gives an instruction on transmission of aconnection request signal to request connection to the other wirelesscommunication device that has been determined as a new connectiondestination of the target wireless communication device.
 10. A wirelesscommunication device, comprising: a central processing unit (CPU)configured to: receive, with respect to one or a plurality of targetwireless communication devices connected to another wirelesscommunication device, a measurement request signal which requestsmeasurement related to a first propagation status of a first signalbetween a target wireless communication device and the wirelesscommunication device, wherein the measurement request signal istransmitted from the other wireless communication device; based on thereceived measurement request signal, generate a measurement requestresponse signal including a result of the measurement related to thefirst propagation status of the first signal from the target wirelesscommunication device; transmit the measurement request response signalto the other wireless communication device; and receive informationabout a connection destination of the target wireless communicationdevice from the other wireless communication device, wherein the otherwireless communication device determines the information about theconnection destination based on a comparison of a second propagationstatus of a second signal between the other wireless communicationdevice and the target wireless communication device, with the firstpropagation status of the first signal between the wirelesscommunication device and the target wireless communication device. 11.The wireless communication device according to claim 10, wherein: theother wireless communication device transmits a transmission requestsignal that gives an instruction on transmission of a response signalfor the measurement, and wherein the CPU is further configured to:receive the response signal transmitted from the target wirelesscommunication device based on the transmission request signal; andgenerate the measurement request response signal including a result ofthe measurement obtained based on the reception of the response signal.12. The wireless communication device according to claim 11, wherein themeasurement request signal includes information used to identify thetarget wireless communication device that transmits the response signal;and the CPU is further configured to generate the measurement requestresponse signal including identification information identifying thetarget wireless communication device that is a sender of the responsesignal, and including a result of the measurement obtained with respectto the target wireless communication device identified by theidentification information.
 13. The wireless communication deviceaccording to claim 11, wherein the transmission request signal includesa trigger frame defined by IEE 802.11ax.
 14. The wireless communicationdevice according to claim 11, wherein the result of the measurementincludes distance indicator information that serves as an indicator of adistance between the target wireless communication device and thewireless communication device.
 15. The wireless communication deviceaccording to claim 14, wherein the CPU is further configured to performthe measurement on a basis of reception timing of the response signal orthe received response signal.
 16. The wireless communication deviceaccording to claim 14, wherein the distance indicator informationincludes reception intensity of the response signal, reception time ofthe response signal, time from transmission time of the response signalto the reception time of the response signal, or an error property atthe time of reception of the response signal.
 17. The wirelesscommunication device according to claim 16, wherein the measurementrequest signal includes delay amount information used to identifytransmission timing of the response signal from the target wirelesscommunication.
 18. A wireless communication device, comprising: acentral processing unit (CPU) configured to: receive a connectionrequest inducing signal that has been transmitted from a first wirelesscommunication device connected, and that gives an instruction ontransmission of a connection request signal which requests connection toa second wireless communication device determined as its own newconnection destination, wherein wherein the reception of the connectionrequest inducing signal is based on a comparison of a second propagationstatus of a second signal between the first wireless communicationdevice and the wireless communication device, with a first propagationstatus of a first signal between the second wireless communicationdevice and the wireless communication device; and transmit theconnection request signal to the second wireless communication deviceaccording to the connection request inducing signal.
 19. The wirelesscommunication device according to claim 18, wherein the CPU is furtherconfigured to: receive a transmission request signal that has beentransmitted from the first wireless communication device, and that givesan instruction on transmission of a response signal for measurementrelated to the first propagation status of the first signal to/from thesecond wireless communication device, and receive the connection requestinducing signal, transmitted from the first wireless communicationdevice, based on the transmission of the response signal.
 20. Thewireless communication device according to claim 19, wherein the secondwireless communication device that serves as its own new connectiondestination is determined by the first wireless communication device ona basis of a result of the measurement.